B CNG THNG

TRNG I HC CNG NGHIP H NI

Khoa Cng Ngh Ho

- - - - -o0o- - - - -

KHA LUN TT NGHIP

ti: Nghin cu qu trnh trng hp poly(hydroxamic axit) t acrylamit v vinylsunfonic axit tch kim loi t him Neodym, Xeri Gio vin hng dn : TS. Nguyn Th Thanh Mai TS. Trnh c Cng

Sinh vin thc hin : Nguyn Th M Hng

H Ni 2015

LI CM NKha lun tt nghip ny c thc hin ti Phng vt liu polyme - Vin Ha hc - Vin Hn lm Khoa hc v cng ngh Vit Nam.

Em xin trn thnh cm n TS. Trnh c Cng hng dn tn tnh v to mi iu kin thun li cho em trong sut qu trnh thc hin v hon thnh kha lun tt nghip ny.

Em cng xin gi li cm n ti c Nguyn Th Thanh Mai cng ton th cc thy c trong Khoa Cng Ngh Ha hc-Trng i hc Cng Nghip H Ni truyn t cho em nhng kin thc b ch v to mi iu kin em c kh nng hon thnh kha lun tt nghip ny.

Em xin cm n cc thy, cc c v cc anh ch thuc phng vt liu polyme - Vin ho hc - Vin Hn lm Khoa hc v Cng ngh Vit Nam dy bo, gip , ng vin v to iu kin cho em hon thnh kha lun tt nghip ny.

Em xin chn thnh cm n!

H Ni, ngy 08 thng 05 nm 2015

Sinh Vin

Nguyn Th M Hng

DANH MC CC K HIU V CH VIT TT

VSA:

Vinylsulfonic axit APS:

Amoni pesunfat

PVSA:Poly(vinylsulfonic axit)IR:

Ph hng ngoi

KLPT:Khi lng phn t trung bnh

PHA-VSA:Poly(vinylsulfonic axit-acrylamit)

MBA: N,N- metylenebisacrylamit

APS:

Amoni pesunfat

NTH:Nguyn t t himKLH:Kim loi t him

PHA:

Poly(hydroxamic axit)

EDTA: ethylen triamintetra axetic axit

DANH MC CC HNH10Hnh 1.1: Hp cht acrylamit

10Hnh 1.2: Vinylsunfonic axit

11Hnh 1.3: Poly (Hydroxamic axit)

12Hnh 1.4: Nhm chc hyroxamic dng tautome ha gia xeton v enol

12Hnh 1.5: C ch phn ng gia PHA v ion KLH

22Hnh 2.1: Phn ng ng trng hp p(AM-co-VSA)

23Hnh 2.2: S bin tnh tng hp PHA

34Hnh 3.1: Ph hng ngoi ca VSA

34Hnh 3.2: Ph hng ngoi ca acrylamit

36Hnh 3.6: Mt s hnh nh SEM ca p(AM-co-VSA)

37Hnh 3.7: nh hng ca nng n qu trnh hp ph Nd3+, Ce4+

38Hnh 3.8: nh hng ca pH n kh nng hp ph ca nha

38Hnh 3.9: nh hng ca thi gian n kh nng hp ph ca nha

DANH MC CC BNG15Bng 1.1: Tnh cht vt l ca Nd v Ce

29Bng 3.1: nh hng ca nhit v thi gian phn ng n qu trnh ng trng hp VSA v AM

31Bng 3.2: nh hng ca nng cht khi mo v thi gian phn ng n qu trnh ng trng hp p(AM- co-VSA)

32Bng 3.3: nh hng ca hm lng cht to li

33Bng 3.4: nh hng ca cht hot ng b mt n qu trnh ng trng hp

MC LC

iLI CM N

iiDANH MC CC K HIU V CH VIT TT

vMC LC

1M U

2CHNG 1: TNG QUAN

21.1. C S L THUYT CA PHN NG NG TRNG HP

51.1.1.Trng hp huyn ph

91.1.2.Cc yu t nh hng n qu trnh trng hp huyn ph

101.2. acrylamit (AM)

101.3. Vinylsunfonic axit (VSA)

111.4. Poly(hydroxamic axit) (PHA)

141.5. NGUYN T T HIM NEODYM, XERI

181.6. HP PH

21CHNG 2: THC NGHIM

212.1. HA CHT, DNG C, THIT B

212.1.1. Ha cht

212.1.2. Dng c, thit b

222.2. PHNG PHP TIN HNH

222.1.1. ng trng hp

232.2.3. Nghin cu cc yu t nh hng n qu trnh trng hp p(AM-co-VSA) bng phng php huyn ph

242.2.4. Qu trnh hp ph Nd3+, Ce4+ bng PHA

252.3. PHNG PHP PHN TCH NH GI

252.3.1. Hm lng phn gel theo khi lng

252.3.2. Ph hng ngoi

262.3.3. Phng php hin vi in t SEM

262.3.4. hp ph

272.3.5. Phng php ICP-MS

29CHNG 3: KT QU V THO LUN

293.1. NH HNG CA NHIT V THI GIAN PHN NG

303.2. NH HNG CA NNG CHT KHI MO V THI GIAN PHN NG

323.3. NH HNG CA HM LNG CHT TO LI

323.4. NH HNG CA CHT N NH HUYN PH N QU TRNH PHN NG

333.6. C TNH HA L CA SN PHM

333.6.1. Ph hng ngoi

363.6.2. SEM

363.7. KHO ST NNG U NH HNG N HP PH CA NHA

373.8. NH HNG CA pH N KH NNG HP PH CA NHA.

383.9. NH HNG CA THI GIAN N KH NNG HP PH CA NHA

39KT LUN

40TI LIU THAM KHO

M UTrong nhng nm gn y, cng vi s pht trin ca khoa hc v cng ngh, th vt liu polyme cng c nghin cu v ng dng vo i sng trong nhiu lnh vc khc nhau. Trong s , nha c cha nhm chc hydroxamic axit c nhiu ng dng quan trng v thit thc trong thc t. Nha poly(hydroxamic axit) c s dng nh nha trao i ion trong x l nc, dng thu hi cc ion kim loi, hoc dng tch cc ion kim loi nng v kim loi t him rt hiu qu.

Hin nay, c rt nhiu cc phng php khc nhau ch to nha trong thnh phn c cha nhm chc hydroxamic axit nh: i t polyacrylamit, polyacrylic axit, polymetylacrylathoc i t acrylcacbohydroxamic vi hydroxylamin trong iu kin thch hp. Trong , c phng php i t poly(acrylamit-co-vinylsulfonic axit) ang c nghin cu v s dng nhiu. V c th theo nhiu phng php tin hnh khc nhau nh: trng hp dung dch, trng hp huyn ph, trng hp nh tng, trng hp khi... theo c ch gc t do. Trong c phng php trng hp huyn ph thng c s dng trong phng th nghim v sn phm c kh nng hp ph, gii hp hiu qu nguyn t t him, v khng th khng k n hai nguyn t t him quan trng Neodym, Xeri.

V vy, ti kha lun tt nghip ca em l: nghin cu qu trnh trng hp poly(hydroxamic axit) t acrylamit v vinylsulfonic axit tch kim loi t him Neodym, Xeri vi nhng vn ch yu l :

Tng hp poly(hydroxamic axit) v nghin cu cc yu t nh hng n qu trnh tng hp (nhit , nng cht khi mo, nng monome, thi gian phn ng).

Bc u nghin cu s dng copolyme thu c hp ph mt s ion kim loi Nd(III), Ce(IV) lm tin cho vic s dng PHA trong vic tch cc nguyn t t him nhm nh.

CHNG 1: TNG QUAN

1.1. C S L THUYT CA PHN NG NG TRNG HPQu trnh ng trng hp l qu trnh trng hp hai hay nhiu monome m sn phm polyme sinh ra c cc mt xch monome sp xp ngu nhin (copolyme ngu nhin), sp xp lun phin u n, hoc cc mt xch monome khc nhau to thnh cc on mch khc nhau trn polyme [6]. i phn t nhn c t qu trnh ng trng hp c gi l copolyme. Thnh phn cu to ca copolyme cha cc mt xch to nn t cc monome ban u lin kt vi nhau tun theo mt trt t nht nh.

Phn ng ng trng hp thng c s dng ch to cc vt liu polyme c cc tnh cht l ho cn thit m phn ng trng hp khng th c c [10]. t c sn phm theo yu cu, cn phi nghin cu, la chn nguyn liu ban u, phng php trng hp thch hp.

T l cc cu t ban u c mt trong sn phm nhn c t qu trnh ng trng hp thay i trong gii hn rng tu thuc vo kh nng hot ho ca cc monome ban u tham gia phn ng [11,12].

Vic xc nh kh nng phn ng ca cc monome trong qu trnh ng trng hp c ngha thc t hng u. Khi bit c iu ny c th xc nh v tnh ton c din bin ca ton b qu trnh ng trng hp.

Trc ht, xt cc hng s ng trng hp v cc phng php xc nh gi tr s hc ca chng.

Kh nng phn ng ca cc monome v cc hng s ng trng hp

Phn ng pht trinTc phn ng

R1 + M1 R1(1.1)K11. [R1] [M1]

R1 + M2 R2(1.2)K12. [R1] [M2]

R2 + M1 R1(1.3)K21. [R2] [M1]

R2 + M2 R2(1.4)K22. [R2] [M2]

y:

R1 v R2 l cc gc pht trin

M1 v M2 l cc phn t monome

K11, K12, K21, K22 l cc hng s tc phn ng.

Tc tiu th cc monome M1 v M2 trong qu trnh ng trng hp c xc nh:

(1.5)

(1.6)

T phng trnh (1) v (2) ta nhn c:

(1.7)

trng thi dng, nng ca cc gc R1 v R2 c th xem gn nh khng i.

K12. [R1] [M2] = K21. [R2] [M1]

(1.8)

T (7) v (8) ta c:

(1.9)

(1.10)

y: , ; r1, r2 gi l hng s ng trng hp.

Khi ng trng hp hai monome, c th c cc t l hng s ng trng hp sau:

r1 < 1, r2 > 1, tc l K12 > K11 v K22 > K21, gc R1 v R2 phn ng vi M2 d hn vi M1.

r1 > 1 v r2 < 1, tc l K12 < K11 v K22 < K21, gc R1 v R2 phn ng vi M1 d hn vi M2.

r1 < 1 v r2 < 1, tc l K12 > K11 v K22 < K21, gc R1 d phn ng vi M2, cn gc R2 d phn ng vi M1.

r1 > 1 v r2 > 1 trng hp ny rt t gp, K11 > K12 v K22 > K21, ngha l gc R1 d phn ng vi M1 v gc R2 d phn ng vi M2.

r1 = r2 = 1, rt t gp, gc R1 v R2 ng nht d phn ng vi c hai monome [9].

C rt nhiu phng php xc nh hng s ng trng hp nh: phng php Xacat [13-16], phng php t hp cc ng cong, phng php tng giao cc ng thng, phng php tch phn ca Mai - Liux, phng php Kelen - Tudos, phng php Fineman Ross. 1.1.1. Trng hp huyn phMt lng ln polyme nhn to t bit l nhng cht do tng hp c sn xut bng phng php huyn ph. Thut ng trng hp huyn ph c p dng trong h thng m monome khng ha tan trong nc hoc cc monome tan trong nc m khng tan trong dung mi hu c. Trong thc t thut ng trn cn ty thuc vo bn cht ca monome m ta chn nc hay dung mi hu c l pha lin tc. Cc ht huyn ph l nhng ht lng l lng trong pha lin tc [4].

Trong trng hp huyn ph cht khi mo c ha tan trong pha monome, m c phn tn thnh mi trng phn tn hnh thnh git. ha tan ca pha monome phn tn (git) cng nh monome sn phm trong mi trng phn tn thng rt thp [7]. Phn th tch ca pha monome thng nm trong khong t 10% n 50%. Phn ng trng hp c th c tin hnh vi th tch monome thp hn nhng thng khng hiu qu v mt kinh t [17]. phn th tch cao hn, nng ca pha lin tc c th khng lp y khng gian gia cc git. Qu trnh trng hp khng pha git, v trong hu ht trng hp xy ra theo c ch gc t do. Trng hp huyn ph thng yu cu thm vo mt lng cht n nh chng keo t v phn tn cc git ban u v th cng nh hng n ht polyme to thnh, ph thuc vo cn bng gia cc ht c phn tn v cc ht b keo t. iu ny c th khng ch bng cch s dng cc ht v tc khuy khc nhau, phn th tch ca pha monome, loi v nng cht n nh c s dng. Ht polyme c ng dng nhiu trong cng ngh nh cht do c. Tuy nhin ng dng nhiu nht ca chng l trong mi trng phn tch sc k (nh nha trao i ion v lm km hot ng ca enzym) [18]. Cc ng dng ny thng yu cu din tch b mt ln, iu cn thit hnh thnh cc l xp (vi kch thc yu cu) trong cu trc ht.Ht polyme c th c lm xp bng cch cho dung dch cht pha long tr (porogen ) vo pha monome, c th chit ra sau khi trng hp. C th b sung vo pha monome cht n nh UV (xeton v este vng), cht n nh nhit (dn xut etylen oxit v mui v c kim loi), cht bi trn v to bt (porogen).

Thut ng trng hp huyn ph c p dng trong h thng m cc monome khng ho tan trong nc v trng hp huyn ph ngc l cc monome tan trong nc m khng tan trong dung mi hu c [20,21]. Trong thc t thut ng trn c s dng tu thuc vo bn cht ca monome m ta chn nc hay dung mi hu c l pha lin tc. Cc ht huyn ph l nhng ht lng l lng trong pha lin tc. Cht khi mo c th ho tan trong monome lng hoc pha lin tc. Cng c th gi qu trnh trng hp huyn ph l qu trnh trng hp ht v n l bin th ca qu trnh trng hp khi, trng hp dung dch [19]. Trong qu trnh trng hp huyn ph c s dng cht hot ng b mt v cc cht n nh huyn ph.

Cht n nh polyme s dng trong trng hp huyn ph ngc gm cc copolyme khi poly-(hydroxyl-stearic axit)-co-poly(etylen oxit) [22,23]. Cht hot ng b mt s dng trong huyn ph du trong nc gm Span, Tween v cc cht nh ho anion (natri 12-butinoyloxy-9-octadecanat), cc keo bo v nh gelatin [24].

Mt trong nhng yu t quan trng nh hng ti trng hp huyn ph l qu trnh khuy, cht hot ng b mt v cht n nh huyn ph. Kch thc ca cc ht polyme nhn c c ng knh trong phm vi nh v ph thuc vo loi thit b phn ng v tc khuy.

Nhiu nghin cu cho thy, ng hc phn ng trong trng hp huyn ph rt ging vi ng hc ca trng hp khi (khi khng c cht pha long monome no). Quan st ny xut rng trong trng hp huyn ph, iu kin nh ho (iu kin khuy, kch thc v nng ht nh tng/loi cht n nh) c rt t nh hng n ng hc. Hn na, c th kt lun rng bt k s chuyn khi lng no gia hai pha trong nh tng cng khng nh hng n vn tc phn ng. Tr ngi ln ch yu trong thit k phn ng trng hp huyn ph. V vy, l s hnh thnh nh tng n nh, u tin c phn b kch thc ng nht. Ht monome ln bao gm lng ln gc t do (c th nhiu khong 108) v iu gii thch ti sao trng hp huyn ph ni chung c c ch tng t nh trng hp khi, c bit l khi polyme ho tan trong monome.

Trng hp huyn ph c p dng trong h thng m cc monome khng ho tan trong nc v trng hp huyn ph ngc l cc monome tan trong nc m khng tan trong dung mi hu c. Trong thc t thut ng trn c s dng tu thuc vo bn cht ca monome m ta chn nc hay dung mi hu c l pha lin tc. Cc ht huyn ph l nhng ht lng l lng trong pha lin tc. Cht khi mo c th ho tan trong monome lng hoc pha lin tc. Cng c th gi qu trnh trng hp huyn ph l qu trnh trng hp ht v n l bin th ca qu trnh trng hp khi, trng hp dung dch. Trong qu trnh trng hp huyn ph c s dng cht hot ng b mt v cc cht n nh huyn ph. Nhiu nghin cu cho thy, ng hc phn ng trong trng hp huyn ph rt ging vi ng hc ca trng hp khi, trng hp dung dch. Trong trng hp huyn ph th s hnh thnh nh tng n nh v s phn b kch thc ng nht c u tin. Khi cc git monome ln bao gm lng ln gc t do th phn ng trong git nh l phn ng trong khi hay dung dch v iu gii thch ti sao trng hp huyn ph ni chung c c ch tng t nh trng hp khi v trng hp dung dch.

Phng php trng hp huyn ph c thun li l qu trnh truyn nhit rt tt, c an ton cao, trng lng phn t polyme thu c ln v c th tin hnh nng monome cao. Tuy nhin phng php ny cng c nhc im so vi phng php trng hp khi l phi c cng on tch v lm kh sn phm ra khi pha lin tc v cu t c s dng phn tn v chng s kt t nhng ht monome c th b hp ph ln b mt sn phm polyme.*Khi mo bng cc mui pesunfat

Cc mui pesunfat nh kali pesunfat, natri pesunfat hay amoni pesunfat thng c s dng khi mo qu trnh trng hp v ng trng hp gc t do.

Dung dch amoni pesunfat b phn hu theo thi gian khong mt vi thng. Nu nhit cao th s phn hu cng nhanh. Ngoi ra n cn b phn hu trong khng kh m v trong ru. S phn hu ca pesunfat trong dung dch nc theo cc phn ng sau.

+ H2O 2 + 1/2 O2 (1.11)

H2S2O8 + H2O H2SO4 + H2SO5 (1.12)

H2SO5 + H2O H2O2 + H2SO4 (1.13)

Trong mi trng kim, trung tnh v axit long th pesunfat b phn hu theo phn ng (1.11) cn mi trng axit mnh th xy ra theo phn ng (1.12, 1.13). Bc ca phn ng phn hu pesunfat trong nc l bc nht v phn ng ny c xc tc bi ion H+. Ngi ta chng minh rng trong mi trng kim v nc th pesunfat phn hu nhit to thnh gc t do ion pesunfat v nng lng hot ho ca qu trnh ny l 35,5 kcal/mol.

Khi un nng dung dch mui pesunfat, n s phn hy to gc sunfat cng cc phn t gc t do khc. I. M. Kolhoff, I. K. Miller ngh c ch i vi s phn hu nhit ca pesunfat trong dung dch nc.

S2O82- 2SO4- (1.14)

2SO4- + 2 H2O 2HSO4- + 2 HO (1.15) 2 HO H2O + 1/2 O2 (1.16) Cc gc t do {SO4- v OH} s tham gia vo qu trnh khi mo phn ng trng hp v ng trng hp. 1.1.2. Cc yu t nh hng n qu trnh trng hp huyn phQu trnh trng hp b nh hng bi cc yu t nh: nhit phn ng, nng cht khi mo, nng monome v dung mi. nh hng ca nhit : Ni chung tt c cc phn ng trng hp u l phn ng to nhit, khi tng nhit , tc phn ng tng v ph thuc vo hiu ng nhit [25]. Khi nhit tng th lm tng vn tc ca tt c cc phn ng ho hc k c cc phn ng c s trong qu trnh trng hp. Vic tng vn tc qu trnh lm hnh thnh cc trung tm hot ng v vn tc pht trin mch ln, do lm tng qu trnh chuyn ho ca monome thnh polyme v ng thi cng lm tng vn tc ca phn ng t mch dn n lm gim trng lng phn t trung bnh ca polyme nhn c.

nh hng ca nng cht khi mo: Khi tng nng cht khi mo, s gc t do to thnh khi phn hu tng ln dn ti lm tng s trung tm hot ng, do vn tc qu trnh trng hp chung tng. Nhng khi khi lng phn t trung bnh ca polyme to thnh gim.

nh hng ca nng monome: Khi tin hnh trng hp trong dung mi hay trong mi trng pha long vn tc ca qu trnh v trng lng phn t trung bnh tng theo nng ca monome. Nu monome b pha long nhiu c kh nng xy ra phn ng chuyn mch do lm gim trng lng phn t trung bnh ca polyme.

nh hng ca dung mi: nh hng ca dung mi n qu trnh phn ng c th l do cc yu t: phn cc, hoc l do xy ra phn ng gia polyme vi dung mi, phn ng monome vi dung mi, hoc gia mch ang pht trin vi dung mi. Dung mi c kh nng phn tn, khuch tn, kim sot phn ng chuyn mch. Cc phn ng ho hc c th kim sot khi c mt ca dung mi nh l pht trin phn ng to gc t do trong qu trnh trng hp, y l mt yu t nh hng quan trng khng theo mong mun.

1.2. acrylamit (AM)

Hnh 1.1: Hp cht acrylamit

- Acrylamit l mt hp cht ha hc c cng thc ha hc C3H5NO, tn thay th l prop-2-3enamit.

- Tnh cht vt l : l cht bt mu trng, khng mi, tinh th rn, ha tan trong nc, etanol, ete v clorofom.

- Tnh cht ha hc: Acrylamit phn hy khi c mt ca axit, bazo, cht oxy ha, st v mui st. N phn hy khng nhit to thnh amoniac v phn hy nhit to ra kh cacbon monoxit, cacbon ioxit v cc oxit nit.

1.3. Vinylsunfonic axit (VSA)

Hnh 1.2: Vinylsunfonic axit

Axit Vinylsulfonic l hp cht hu c c cha lu hunh, c cng thc ha hc l C2H4O3S, tn thay th l ethenesulfonic acid [30].

Vinylsulfonic axit (VSA) c cng thc ha hc CH2=CHSO3H, l hp cht hu c cha lu hunh, l monomer vinyl n gin nht c cha gc sulfonic axit.

L cht lng khng mu, c phn ng trng hp to poly(vinylsulfonic axit) (PVS) v ng trng hp to copolyme. PVS mang tnh axit.

Vinylsulfonic axit (VSA) l cht c kh nng phn ly axit cao v dn ion cao (0,04 - 0,11 S.cm-1).

N c s dng rng ri nh l nha trao i ion, mng dn proton, l cht xc tc cho cc phn ng tng hp axit, l mt tc nhn phn tn nc cho cc vt liu carbon, v l mt tc nhn axit tng hp cc polyme, do n c phn ly thnh ion ln, hm lng proton cao [26,27].

N c iu ch bng cch kh nc ca axit isethionic :

HOC2H4SO3H CH2CHSO3H + H2O.1.4. Poly(hydroxamic axit) (PHA)

Cng thc cu to n gin ca poly (Hydroxamic axit):

Hnh 1.3: Poly (Hydroxamic axit)Trong , P l polime xng sng.

Trong thnh phn ca nha PHA cha 2 nhm chc chnh l CONHOH v COOH. Nhm COOH c trong thnh phn nha l v trong qu trnh thy phn mt phn CONHOH b thy phn to thnh COOH.

Poly(hydroxamic axit) c tng hp theo nhiu phng php khc nhau nh: i t polyacrylamit, poly(acrylic axit), poly(metylacrylat)hoc i t acrylcacbohydroxamic vi hydroxylamin trong iu kin thch hp [28].

Sau qu trnh tng hp thu c nha PHA c thnh phn nguyn t ca poly (hydroxamic axit) cha ch yu 4 nguyn t: C, H, N, O. Trong gm 44,69% C, 6,68% H, 16,05% N, 31,46% O. Ta thy hm lng nguyn t N v O cao hn nhiu so vi H cho thy mc chuyn i cao ca cc nhm axit hydroxmic.

Poly(hydroxamic axit) l loi polyme c kh nng to phc vng cng bn vi nhiu ion kim loi khc nhau. Nhm hydroxamic axit trong polyme c cng thc chung l RCO-RHOH (R l ankyl hoc aryl) v xut hin hai dng tautome ha gia xeton v enol nh trong hnh 1.4

Hnh 1.4: Nhm chc hyroxamic dng tautome ha gia xeton v enol

Giai on tch v tinh ch c th s dng phng php sc k trao i ion, trong cht nhi ct l PHA ng vai tr lm pha tnh v pha ng l dung dch mui ca kim loi cn tch v tinh ch.Nhm hydroxamic axit ca polyme trn c s poly(hydroxamic axit) c kh nng to phc vng cng i vi nhiu ion kim loi [29]. Trn c s c nhiu nghin cu c tin hnh nhm tng hp v ng dng poly(hydroxamic axit) trong vic tch, chit v tinh ch cc kim loi qu nh cc nguyn t phng x U, Nd.., s dng tch cc nguyn t t him ra khi hn hp.

C ch phn ng gia nha PHA vi ion KLH c biu din trong hnh hnh 1.5.

Hnh 1.5: C ch phn ng gia PHA v ion KLH

So vi phng php s dng nha trao i ion cc polyme trn c s poly(hydroxamic axit) c kh nng tch tt hn, iu ny v nha trao i ion ch n thun c kh nng trao i nhng ion c th ca n vi cc ion ca NTH trong dung dch trong khi polyme trn c s poly(hydroxamic axit) ngoi kh nng trao i ion cn c cha cc nhm chc nng nh CONHOH, - SO3H,.. c th to lin kt phc vng cng bn vi cc ion kim loi t him v vy kh nng tch s t hiu qu cao hn so vi nha trao i ion thng thng. ng thi cc tc nhn c kh nng to phc vng cng ni chung v poly(hydroxamic axit) ni ring lm tng h s tch i vi cc ion kim loi. iu ny c ngha rt ln trong vic s dng poly(hydroxamic axit) trong phng php to phc trao i ion dng hydrogel tch chit cc nguyn t kim loi.

Phng php s dng mt s polyme trn c s poly(hydroxamic axit) (PHA) tch cc nguyn t t him l mt trong nhng hng nghin cu v ang c nghiu nh khoa hc trn th gii quan tm. Phng php ny c cho l n gin hn phng php chit v tiu tn t ha cht tch v tinh ch. T nhng u im vt tri trn so vi cc phng php khc nn phng php ny s c s dng nhiu hn.

C nhiu phng php tng hp PHA, v d i t poly(vinylsunfonic axit-co-acrylamit), poly(acrylamit), poly(acrylic axit), poly(metylacrylat), poly(acrylonitril), hoc i t acrylcacbohydroxamic vi hydroxylamin trong iu kin thch hp .P. Selvi v cc cng s tin hnh tng hp PHA t acrylonitril trong s c mt ca cht khi mo benzoylperoxit v cht to li divinyl benzen. Qu trnh thc hin sau l bin tnh polyme to c bng NH2OH.HCl trong s c mt ca CH3COONa. Sau qu trnh tng hp thu c nha PHA c thnh phn nguyn t ca poly (hydroxamic axit) cha ch yu 4 nguyn t: C, H, N, O. Trong gm 44,69% C, 6,68% H, 16,05% N, 31,46% O. Ta thy hm lng nguyn t N v O cao hn nhiu so vi H cho thy mc chuyn i cao ca cc nhm axit hydroxamic.Hossein v cng s tin hnh tng hp PHA i t axit acrylcacbohydroxamic. Trong nghin cu ny cc tc gi tng hp axit acrylcacbohydroxamic i t etylacrylat, acrylamit, axit acrylic v hydroxylamin hidroclorua (NH2OH.HCl). Sn phm acrylcacbohydroxamic sau c em trng hp trong iu kin thch hp to ra PHA.Wan MD v nhm nghin cu tng hp PHA t poly(etylacrylat divinyl benzen). Trong poly(etylacrylat) c tng hp bng phng php trng hp huyn ph vi s c mt ca divinyl benzen. Cc tc gi tin hnh chuyn ha poly(metylacrylat divinyl benzen) thnh PHA bng phn ng vi hydroxyl amoni clorua trong mi trng thch hp.

Trong cng trnh nghin cu ca M. Rahman v cng s, cc tc gi tin hnh tng hp PHA bng cch ghp poly(metylacrylat) (PMA) ln tinh bt, sau sn phm thu c em phn ng vi hydroxylamin.Taek Seung Lee, Dong Won Jeon tng hp nha poly (hydroxamicaxit) t etylacrylat (EA) v divinylbenzen (DVB),vi s c mt ca 2,2,4trimetylpentan (TMP). Hanssan v cng s tng hp poly(hydoxamic axit) t polyacrylamit (PAA) [31]. PAA c tng hp bng vic trng hp ca monome acrylamit vi s c mt ca N,N-methylene-bis-acrylamit (MBA). Neira-Carrillo v cc cng s tin hnh tng hp PVSA c s dng cht khi mo l APS, dung dch sau phn ng c kt ta trong aceton. Suresh Kuarm v cc cng s tin hnh tng hp poly(vinylsulfonic axit) t dng mui natri ca dung dch vinylsulfonic. Qu trnh tng hp c thc hin theo phng php Breslows tin hnh trong hai bc. Trong bc u tin, trng hp mui natri vinylsulfonate thu c polyvinylsulfonic dng mui (Na-PVSA), trng lng phn t trung bnh ca n c xc nh khong ~55,000 bng phng php o nht c trng. Bc tip theo, poly(vinylsulfonic axit) (PVSA) c tng hp thng qua k thut trao i ion. Xc nh c pH ca dung dch PVSA 0,01N vo khong 2,83. Na-PVSA l tin thn ca PVSA v c c trng bi k thut XRD, DSC v FT - IR.1.5. NGUYN T T HIM NEODYM, XERI

Neodym, Xeri l 2 trong nhng NTH nhm nh quan trng [1].Cc c trng nguyn t v tnh cht vt l ca Nd, Ce c th hin trong bng 1.1.Bng 1.1: Tnh cht vt l ca Nd v CeNguyn tNeodymXeri

Th t nguyn t6058

S oxi ha3, 44, 3, 2

Nguyn t lng144140

Cu hnh electron[Xe]4f46s2[Xe]4f15d16s2

Cu trc tinh thLc phngLc phng tm mt

Bn knh nguyn t (A0)1.825

Mu scBc trngBc trng

Trng thi vt chtCht rnCht rn

Nhit nng chy t0nc (0C)1024795

Nhit si t0s (0C)30743443

T khi (g/cm3)7,016,77

Cc hp cht Nd, Ce ch yu th hin mc oxi ha +3. V vy chng tnh cht ha hc c trng l tnh kh mnh. Kim loi dng tm bn trong khng kh kh. Trong khng kh m b m c nhanh chng v b ph mng cacbonat baz c to nn do tc dng vi H2O v CO2[2]. 200 4000C, chy trong khng kh to thnh oxit v nitrua.

Tc dng vi halogen nhit khng cao, vi N, S, C, Si, P H khi un nng

Tc dng chm vi nc ngui v nhanh vi nc nng to thnh hidroxit v gii phng H2.

Tan d dng trong dung dch axit, tr HF v H3PO4 v to mui LnF3, LnPO4 t tan.

Khng tan trong kim k c khi un nng.

nhit cao c th kh c nhiu oxit kim loi.

Kh nng to phc: Ln3+ c kh nng to phc vi nhng phi t v c thng thng nh: NH3, Cl-, CN-,NO3-, SO42-,... nhng phckm bn, ngc li Ln3+ c th to phc tng i bn vi nhng phi t a cng, nhng phi t hu c nh: C2O42-, -ixetonat, EDTA, DTPA, IMDA,...

Cc nguyn t t him l nguyn liu cc k quan trng cho nhiu ngnh khoa hc, k thut v cng ngh. Vai tr ca nguyn t t him trong cng ngh ch to vt liu l khng th thiu c [3].

Cc nguyn t t him c dng lm xc tc cracking du m, xc tc t him c dng trong qu trnh tng hp amoniac, xilen v nhiu hp cht hu c khc. Nguyn t t him cn c dng lm xc tc lm sch kh thi t, xc tc trong l t rc y t. So vi cc xc tc cng loi cha nguyn t qu (Pt), xc tc cha nguyn t t him bn vi nhit, bn ha hc, c hot tnh cao hn v iu quan trng l gi thnh r hn. S dng mt thi gian cc xc tc t him c phc hi bng cch ra bng dung dch HCl long.

Nhiu kim loi t him c tit din bt ntron ln, nn c dng hp th ntron nhit trong l phn ng ht nhn.

Trong cng nghip luyn kim, cc nguyn t t him c dng cho thm vo mt s hp kim. Chng hn sn xut gang bin tnh ngi ta cho thm cc nguyn t t him. Do tc dng ca cc nguyn t t him, khng nhng mt s tp cht c hi trong gang b loi ra m cu trc ca cacbon trong gang cng bin i lm gim tnh gin ca gang v gang bin tnh c th thay thp. Thm nguyn t t him vo hp kim ca Magie lm cho hp kim bn c hc v bn nhit hn. Nhng hp kim ny c dng ch to thit b trong my bay. Thp cha 6% xeri dng lm dng c phu thut trong y t.

Trong lnh vc vt liu t, cc nguyn t t him cng ng vai tr quan trng. C vt liu t cha t him c phn t v mt nng lng t cao, gi thnh r v s dng rng ri trong lnh vc ch to ng c in, my gia tc proton, my tnh. l cc hp kim NdFeB, SmCo6, SmFeCu c t tnh mnh gp nhiu ln nam chm lm bng st. Dng ch to cc thit b trn my bay v tu v tr.

Trong cng nghip thy tinh, cc nguyn t t him c s dng kh nhiu: CeO2, Nd2O3 c dng kh mu thy tinh. Mt s nguyn t t him c s dng nhum mu thy tinh nh Nd2O3 (tm hng), CeO2 (vng chanh),Y2O3 v Eu2O3 c dng ch to gm k thut v dn dng chu nhit cao.

Cc nguyn t t him cn c dng ch to vt liu pht quang c hiu sut pht quang cao, tn t nng lng. c s dng lm bt cho n hunh quang, n compac mu, n hnh tivi.

Trong nng nghip cc nguyn t t him c dng ngm tm ht ging, sn xut phn bn vi lng. Nguyn t t him to ra cc hp cht enzim lm cho cy trng c kh nng khng c su bnh, cho nng sut cy trng cao, bo v mi trng.

Cc sn phm ca nguyn t t him Neodym c s dng rng ri trong cc ngnh cng nghip, nng nghip, y hc, Cc lnh vc ng dng chnh: cht xc tc, my lc IR, laser, cht nhum v nam chm vnh cu.

Trong cng nghip luyn kim, Xri c thm vo cc hp kim lm gim tnh gin, tng bn c hc v bn nhit. Trong thnh phn ca thp c cha Xri c s dng lm dng c phu thut trong y t.

Trong cng nghip thy tinh, th n c ng dng kh mu v nhum m thy tinh. Ngoi ra, cn c s dng lm bt mi bng dng c bng thy tinh v qu.

Ngoi ra, Xri cn c s dng ch to cc thit b trong my bay, tu v tr, ...

Trong , hai nguyn t thuc nhm nh: Nd, Ce l nhng nguyn t rt quan trng v cn thit trng cng nghip, khoa hc k thut [8]. V vy vic nghin cu thu hi v tch cc nguyn t trn ra khi nhau l rt cn thit. Hin nay tch cc nguyn t t him, ngi ta thng s dng cc hp cht polyme, c bit l nha Poly hydroxamic axit (PHA) v dn xut ca n.

1.6. HP PHHp ph l qu trnh tch ly cht trn b mt phn cch cc pha (kh - rn, lng - rn, kh - lng, lng - lng).

Cht hp ph l cht m phn t lp b mt c kh nng ht cc phn t ca pha khc nm tip xc vi n. Cht hp ph c b mt ring cng ln th kh nng hp ph cng mnh. B mt ring l din tch b mt n phn t tnh i vi lng cht hp ph.

Cht b hp ph l cht b ht ra khi pha th tch n tp trung trn b mt cht hp ph.

Thng thng qu trnh hp ph l qu trnh ta nhit.

S hp ph xy ra do lc tng tc gia cc phn t cht hp ph v cht b hp ph. Ty theo bn cht ca lc tng tc m ngi ta phn bit hp ph vt l v hp ph ha hc.

Hp ph vt l c gy ra bi lc Vander Waals gia pn t cht b hp ph v b mt cht hp ph, lin kt ny yu, d b ph v. V vy hp ph vt l c tnh thun nghch cao. Cu trc in t ca cc phn t cc cht tham gia qu trnh hp ph vt l t b thay i. Hp ph vt l khng i hi s hot ha phn t do xy ra nhanh.

Hp ph ha hc gy ra bi lc lin kt ha hc gia b mt cht hp ph v phn t cht b hp ph, trong c nhng lc lin kt mnh nh lc lin kt ion, lc lin kt cng ha tr, lc lin kt phi tr.. .gn kt nhng phn t cht b hp ph vi nhng phn t ca cht hp ph thnh nhng hp cht b mt. Nng lng lin kt ny ln (c th ti hng trm kJ/mol), do lin kt to thnh bn kh b ph v. V vy hp ph ha hc thng khng thun nghch v khng th vt qu mt n lp phn t.

Trong hp ph ha hc, cu trc in t ca cc phn t ca cc cht tham gia qu trnh hp ph c s bin i su sc dn n s hnh thnh lin kt ha hc. S hp ph ha hc cn i hi s hot ha phn t do xy ra chm.

Trong thc t, s phn bit hp ph vt l v hp ph ha hc ch l tng i v ranh gii gia chng khng r rt. Mt s trng hp tn ti ng thi c hai hnh thc hp ph. vng nhit thp thng xy ra hp ph vt l, khi tng nhit kh nng hp ph vt l gim, kh nng hp ph ha hc tng ln.* M hnh ng hc hp phi vi h hp ph lng - rn, ng hc hp ph xy ra theo mt lot giai on k tip nhau:

Cht b hp ph chuyn ng ti b mt cht hp ph. y l giai on khuch tn trong dung dch.

Phn t cht b hp ph chuyn ng ti b mt ngoi ca cht hp ph cha cc h mao qun. y l giai on khuch tn mng.

Cht b hp ph khuch tn vo bn trong h mao qun ca cht hp ph. y l giai on khuch tn trong mao qun.

Cc phn t cht b hp ph c gn vo b mt cht hp ph. y l giai on hp ph thc s.

Trong tt c cc giai on , giai on c tc chm s quyt nh hay khng ch ch yu qu trnh ng hc hp ph. Vi h hp ph trong mi trng nc, qu trnh khuch tn thng chm v ng vai tr quyt nh.* Cc yu t nh hng n qu trnh hp ph

- Qu trnh hp ph b nh hng rt nhiu bi pH ca mi trng. Khi pH ca mi trng thay i dn ti s thay i bn cht ca cht hp ph v nhm chc b mt, th oxi ha kh, dng tn ti ca hp cht , c bit i vi cc cht c phn cc cao, cc cht c tnh lng tnh, cht c tnh axit, baz yu. i vi mt s cht b hp ph c phn cc cao, qu trnh hp ph xy ra do tng tc tnh in thng qua lp in tch kp.

- nh hng ca dung mi: hp ph trong dung dch l hp ph cnh tranh, ngha l khi cht tan b hp ph cng mnh th dung mi b hp ph cng yu. Dung mi c sc cng b mt ln th cht tan cng d b hp ph. Cht tan trong dung mi nc b hp ph tt hn so vi dung mi hu c.

- Nhit : khi tng nhit s ph thuc trong dung dch gim, tuy nhin i vi nhng cu t tan hn ch, khi tng nhit , tan tng lm cho nng ca n trong dung dch tng ln, do vy kh nng hp ph cng c th tng ln.

Ngoi ra cn c cc yu t khc nh: nng ca cht tan trong dung dch, qu trnh hp ph cnh tranh i vi cc cht b hp ph.

CHNG 2: THC NGHIM

2.1. HA CHT, DNG C, THIT B2.1.1. Ha cht

- Cc ha cht dng cho qu trnh nghin cu u dng tinh khit phn tch hoc tinh khit, bao gm:

+ Acrylamit C3H5NO (AM) (CH2=CH-CONH2) (PA - Trung Quc): tan trong nc, d = 1,12g/cm3, M = 71,08g/mol, im chy 82-85oC, c s dng khng qua kt tinh li.

+ Vinyl Sunfonic axit (VSA) (C2H5O3S) d= 1,37g/ml, M= 108,3 g/mol, im chy 360C, s dng khng qua tinh ch li. + N,N- metylenebisacrylamit (MBA) (cht to li) C7H10N2O5+ Amoni pesunfat (NH2)4S2O8 (APS Trung Quc): tan trong nc ( tan 80g/100ml 25 oC) M = 228,18 g/ml, d = 1,98 g/cm3, im nng chy < 100oC (phn hy), c s dng khng qua tinh ch.

+ Nha poly (hydroxamic axit) c tng hp

+ Cc oxit ca 2 nguyn t t him: Nd2O3, CeO2.

+ Cc ha cht khc c s dng ngay khng qua tinh ch li: Natri hidroxit (NaOH), natri hidrocacbonat(NaHCO3), axit clohidric (HCl), axit nitric (HNO3), natri axetat (NaCH3COO), axit axetic (CH3COOH), Ethylenediamine tetraacetic acid disodium salt (EDTA: C10H14N2O8Na2), phenolphthalein, arsenazo III, nc ct, natri hidrocacbonat (NaHCO3), parafin lng, Span 80.

2.1.2. Dng c, thit b

- My khuy t c gia nhit Heidolph, Serial No: 129603072

- Cn phn tch

- H thng lc, ht, kt ni t sy chn khng Karl Kolb

- Dng c thy tinh: cc thy tinh 100, 250, 400 ml; bnh tam gic; ng ong 50ml; pipet; buret; phu lc; a thy tinh, bnh lc, giy lc.

2.2. PHNG PHP TIN HNH

2.1.1. ng trng hp

Bnh thp hnh tr c 3 c 1000ml c khp ni vi thit b khuy, thit b gia nhit v o nhit (b iu nhit), thit b hi lu, ng dn ng sc kh Nit v phu nh git.

Hn hp dung mi parafin lng v cht n nh huyn ph Span 80 (vi t l span 80/parafin: 0,2% v t l pha monome/hn hp dung mi = 1/4) c a vo bnh phn ng v c gia nhit ti nhit phn ng bng b iu nhit. Cho dng kh nit i vo bnh phn ng t lc bt u gia nhit cho n khi kt thc phn ng ui kh oxy ha tan c trong bnh phn ng. Cht khi mo c thm vo hn hp monome (dung dch phn ng gm cc monome acrylamit v vinyl sunfonic axit vi cc t l thnh phn nghin cu khc nhau nh sn) ch trc khi bt u phn ng v c np vo thit b phn ng bng phu nh git. Tc nh git l 10g/pht, tc ny cho php qu trnh trng hp thc hin nhit n nh. Tc khuy trong qu trnh ng trng hp c duy tr 300 vng/pht. Tip tc duy tr n nh tc khuy v nhit phn ng. Khi kt thc phn ng, hn hp phn ng c lm mt xung nhit phng trong khi khuy. Phn dung dch lng c gn ra khi ht, sau cc ht sn phm c ra bng xyclohecxan loi b dung mi parafin. Sn phm sau c lc v lm kh trong chn khng 70oC ti khi lng khng i.

Hnh 2.1: Phn ng ng trng hp p(AM-co-VSA)2.2.2. tng hp PHA t copolyme p(VSA-co-AM)Ly 50ml dung dch NH2OH.HCl 3,3M vo 150ml nc ct c cha 10g p(VSA-co-AM) kh. Dng my khuy t khuy u hn hp trong 30 pht ti nhi t phng. iu chnh pH bng dung dch chun NaOH. Ly polyme ny ra ra sch bng nc ct sau sy kh ta c PHA. Tip theo, ly 10g p(VSA-co-AM) kh trn cho vo cc cha 150ml nc ct iu chnh dung dch c pH=14 bng 50ml dung dch NaOH 3,9M. Sau tip tc khuy u phn ng ny trong 24h ti nhit phng. Khi kt thc phn ng ly polyme mu trng ny ra sch bng nc ct v ngm trong HCl 3N khong 10 pht ri li ra sch bng nc ct cho n khi ht HCl t do. Ta c PHA-VSA.

Hnh 2.2: S bin tnh tng hp PHA2.2.3. Nghin cu cc yu t nh hng n qu trnh trng hp p(AM-co-VSA) bng phng php huyn ph- nh hng ca nhit v thi gian n qu trnh trng hp AM- VSA, phn ng c tin hnh iu kin: nhit 700C - 900C; thi gian 60 - 240 pht.

- Nghin cu nh hng ca nng cht khi mo n qu trnh ng trng hp AM- VSA, phn ng c tin hnh cc iu kin: nng cht khi mo APS: 0,5% - 2,0% (theo khi lng monome).

- Nghin cu nh hng ca nng cht to li n hp th nc ca AM- VSA, phn ng c tin hnh cc iu kin: nng cht to li MBA: 0.5% - 14% (theo khi lng monome).

- Nghin cu nh hng ca cht hot ng b mt Span 80 n qu trnh trng hp, phn ng c tin hnh iu kin: nng cht n nh huyn ph thay i theo t l: 0.05% - 0,25%.

2.2.4. Qu trnh hp ph Nd3+, Ce4+ bng PHA

* Pha dung dch gc Nd3+ t oxit Nd2O3

Cn chnh xc trn cn phn tch mt lng bng 1,457g Nd2O3, ri ha tan oxit bng 1ml dung dch HNO3 (c) v thm 5ml nc ct, ri un nng dung dch n 800C ui ht axit d. nh mc 250ml ta thu c dung dch Nd(NO3)3 5g/l. Sau xc nh li nng Nd3+ bng dung dch EDTA 0.01M vi thuc th arsenazo III 10-3M pH = 4,75.

* Pha dung dch ion Ce4+ : Tng t nh trn v tin hnh xc nh li nng cc dng dch trn bng dung dch EDTA 0,01M vi thuc th arsenazo III pH = 4,75, s dng m axetat iu chnh pH.Qu trnh hp ph:

Ly Vml dung dch Nd3+, Ce4+ 5g/l cho ln lt vo cc bnh nh mc 50ml c dung dch Nd3+, Ce4+ cc nng nghin cu, Sau khi iu chnh pH, thm 1ml m axetat n nh pH, ri tin hnh nh mc n vch nh mc 50, ri cho ra bnh tam gic c cha mg nha. Tin hnh khuy bng my khuy t nhit 250C. Khuy trong nhng khong thi gian khc nhau. Khi kt thc phn ng lc nha ly dung dch cn li em o quang v o ICP xc nh nng cn bng v tnh hp ph. * Kho st mt s yu t nhit , nng , thi gian nh hng ti qu trnh hp ph:

- Nghin cu nh hng n kh nng hp ph ca nha PHA cc nng : 100 - 700 mg/l.

- Nghin cu nh hng n kh nng hp ph ca nha PHA cc pH: 3 - 7.- Nghin cu nh hng n kh nng hp ph ca nha PHA cc khong thi gian: 30 - 240 pht.

2.3. PHNG PHP PHN TCH NH GI

2.3.1. Hm lng phn gel theo khi lngSn phm sau khi phn ng c sy bng t sy chn khng 60oC n khi lng khng i. Cn mt lng (khong 2g) chnh xc ri tin hnh cho vo ti lc, ngm trong nc ct v ra li bng nc ct sau nhiu ln loi b phn polyme khng to li. Sn phm cn li trong ti c sy li bng t sy chn khng n khi lng khng i. Cn li xc nh khi lng sn phm c to li. Hm lng phn gel ca sn phm c xc nh theo cng thc sau:

Trong : g1v g2 khi lng sn phm kh trc v sau khi khi ra.2.3.2. Ph hng ngoiTin hnh o ph hng ngoi ca polyme trong vng 4000 400 cm-1 trn my IMPACT 400 Nicolet (Hoa K) ti Phng Ph hng ngoi Vin Ha hc Vin Khoa hc v Cng ngh Vit Nam.Phn t hp cht hu c b kch thch ln mc nng lng cao hn chng hp th bc x IR. Da vo c hc c in, nu phn t gm hai nguyn t c momen lng cc th dao ng ca lng cc s to ra mt sng in t, c th tc ng ln sng in t ti, dn ti bng sng hp th tn s dao ng.

Mi mt nhm nguyn t s c nhng dao ng trong mt khong tn s, l tn s dao ng c trng ca nhm .

Cc yu t: s i xng, s tng tc c hc, cng hng Femi, lin kt hidro, cc hiu ng khng gian, cc hiu ng electron, s ng phn ha, trng thi vt l, dung mi nhit u nh hng n v tr, cng , hnh dng bng sng hp th trong ph IR.2.3.3. Phng php hin vi in t SEM

Nguyn tc: Phng php hin vi in t qut (SEM) l s dng chm tia in t c nng lng E = 0,5 3,5 KV to nh mu nghin cu thay v s dng cc bc x kh kin (Visble light) to nh ca vt nh cc knh hin vi quang hc.

Chm tia in t c to ra t catot sau khi i qua hai t quay, s c hi t ln mu. Khi , cc in t th cp s b bt ra do s va chm. Sau chm tia ny c gia tc, khuch i v iu bin ng b vi hnh nh ca vt ri a n mn hunh quang c th t phng i theo yu cu. Phng php hin vi in t qut (SEM) dng nghin cu b mt, kch thc, hnh dng tinh th. Cc mu c chp SEM trn my JEOL-5300 (Nht) ti Phng th nghim nghin cu vi cu trc, Vin K thut nhit i - Vin Khoa hc v Cng ngh Vit Nam.

2.3.4. hp ph

Dung lng hp ph cn bng l khi lng cht b hp ph trn mt n v khi lng cht hp ph trng thi cn bng trong iu kin xc nh v nng v nhit q = (1.1)

Trong : q: Dung lng hp ph cn bng (mg/g)

V: Th tch dung dch cht b hp ph (1)

m: Khi lng cht b hp ph (g)

Co: Nng ca cht b hp ph ti thi im ban u (mg/1)

Ccb: Nng ca cht b hp ph ti thi im cn bng (mg/1)2.3.5. Xc nh hm luongICP-MS l k thut phn tch cc nguyn t v c, da trn nguyn tc ghi o ph theo khi lng (m/z).ICP l ngn la plasma to thnh bng dng in c tn s cao (c MHz) c cung cp bng mt my pht RF. Ngn la plasma c nhit rt cao c tc dng chuyn cc nguyn t trong mu cn phn tch ra dng ion.MS: php ghi ph theo s khi hay chnh xc hn l theo t s gia s khi v in tch (m/z).Mu phn tch c thm vo bng mu chun trc khi em phn tch, sau cng o c ca nguyn t s c em so snh vi cng ca mu chun, t tnh ra kt qu nng tng ng ca tng nguyn t trong mu.u im php o ph ICP- MS:

- Ngun ICP l ngun nng lng kch thch ph c nng lng cao, n cho php phn tch hn 70 nguyn t t Li U v c th xc nh ng thi chng vi nhy v chn lc rt cao (gii hn pht hin t ppb-ppt i vi tt c cc nguyn t).- Kh nng phn tch bn nh lng rt tt do khng cn phi dng mu chun m vn t chnh xc cao; c th phn tch cc ng v v t l ca chng.- Tuy c nhy cao nhng ngun ICP li l ngun kch thch ph rt n nh, nn php o ICP - MS c lp li cao v sai s rt nh.

- Ph ICP - MS t vch hn ph ICP - AES nn c chn lc cao, nh hng thnh phn nn hu nh t xut hin, nu c th cng rt nh, d loi tr.

- Vng tuyn tnh trong php o ICP - MS rng hn hn cc k thut phn tch khc, c th gp hng trm ln v kh nng phn tch bn nh lng rt tt do khng cn dng mu chun m vn cho kt qu tng i chnh xc.

-Ngoi ra ICP-MS cn c s dng nh l mt detector cho LC, CE, GC...

Vi nhiu u im vt tri, k thut phn tch ICP - MS c ng dng rng ri phn tch nhiu i tng khc nhau c bit l trong cc lnh vc phn tch vt v siu vt phc v nghin cu sn xut vt liu bn dn, vt liu ht nhn, nghin cu a cht v mi trng...

CHNG 3: KT QU V THO LUN3.1. NH HNG CA NHIT V THI GIAN PHN NG Nghin cu nh hng ca nhit v thi gian phn ng n qu trnh trng hp khi c nh t l AM/VSA 60/40, t l cht to li MBA 10%, cht khi mo 1,5%, cht hot ng b mt Span 80 l 0,2%.Kt qu nghin cu nh hng ca nhit v thi gian phn ng n qu trnh ng trng hp c th hin bng 3.1

Bng 3.1: nh hng ca nhit v thi gian phn ng n qu trnh ng trng hp VSA v AMNhit (oC)Thi gian (pht)T l AM/VSAc im sn phmGel

(%)DTB((m)

650C3060/40Chy lng--

6060/40Chy lng--

9060/40Khng to ht--

12060/40Khng to ht--

18060/40Khng to ht--

24060/40Chy lng--

700C3060/40Chy lng--

6060/40Khi--

9060/40To ht87-

12060/40To ht91-

18060/40To ht93-

24060/40To ht95-

750C3060/40Chy lng--

6060/40Khi--

9060/40To ht87( 400-450

12060/40To ht91( 400-450

18060/40To ht94( 400-450

24060/40To ht99( 400-450

Trn bng 3.1 th hin mi quan h nh hng ca nhit v thi gian phn ng n qu trnh ng trng hp AM-co-VSA. Kt qu cho thy cc nhit 65oC sn phm to thnh dng chy lng v khng to ht, cc dng sn phm ny khng p ng c yu cu ca mt sn phm l to thnh cc ht ring bit. nhit 700C sn phm ca phn ng to ht nhng ht ny khng trn v hm lng phn gel thu c t 87 n 95%. Mt khc khi chuyn ho thp, sn phm thu c vn cn mt phn cha phn ng khi cc ht sn phm khng to c ht hoc cc ht vn cn dnh kt vi nhau, khng tch ri r rng. nhit 750C sn phm to thnh c dng ht trn tch ri nhau v c hm lng phn gel cao.

Chn nhit 75oC v thi gian phn ng 240 pht l cc iu kin phn ng cho cc nghin cu tip theo.

3.2. NH HNG CA NNG CHT KHI MO V THI GIAN PHN NGKt qu nghin cu nh hng ca cht khi mo v thi gian phn ng n qu trnh ng trng hp c th hin bng 3.2 khi hm lng cht to li MBA l 10%, cht khi mo APS 1,5%, cht hot ng b mt Span 80 l 0,2%, nhit 80oC.Bng 3.2: nh hng ca nng cht khi mo v thi gian phn ng n qu trnh ng trng hp p(AM- co-VSA)

T l monome v thi gianAPS (%)c im sn phmGel (%)DTB ((m)

AM:VSA = 60:40

( =180 pht0,5Khi--

1,0Khi--

1,3To ht98,0(400-450

1,5To ht99,7( 400-450

1,7To ht100( 400-450

2,0To ht100( 400-450

AM:VSA = 60:40

( = 240 pht0,5Khi--

1,0Khi97,2-

1,3To ht98,8(400-450

1,5To ht100( 400-450

1,7To ht100( 400-450

2,0To ht100( 400-450

T kt qu cho thy, hm lng phn gel trong copolyme khng b nh hng nhiu bi nng cht khi mo. Vi phn ng polyme ho theo c ch gc t do, cht khi mo nh hng trc tip trong qu trnh din ra phn ng. Khi hm lng cht khi mo tng dn n s mch ang pht trin tng, tc chuyn mch tng, chiu di mch gim, khong cch gia hai lin kt ngang gim. Ti nng cht khi mo 1,3% bt u hnh thnh ht nhng ht polyme ny ng u thp, trn, trn ca ht nha thp.

Chn nng cht khi mo l 1,5% (theo khi lng monome) v thi gian 240 pht l iu kin cho cc nghin cu tip theo.

3.3. NH HNG CA HM LNG CHT TO LI

Kt qu nghin cu nh hng ca hm lng cht to li n qu trnh phn ng c trnh by trong bng 3.3 khi hm lng cht khi mo APS 1,5%, cht hot ng b mt Span 80 l 0,2%, nhit 80oC, thi gian 240 pht, t l monome AM/VSA l 60/40.Bng 3.3: nh hng ca hm lng cht to li

Hm lng MBA (%)c im sn phmGel (%)DTB ((m)

3To ht96700-800

5To ht96700-800

7To ht98,0(500-600

9To ht99,7( 400-450

10To ht100( 400-450

12To ht100( 400-450

T bng 3.3 cho thy khi tng hm lng cht to li MBA ng knh ca sn phm gim v khi tng hm lng cht to li thi gian phn ng hnh thnh ht nhanh hn, kh nng phn tch sn phm nhanh lm cho ng knh sn phm gim. Chn hm lng cht to li l 10% cho qu trnh nghin cu tip theo3.4. NH HNG CA CHT N NH HUYN PH N QU TRNH PHN NG

Kt qu nh hng ca cht hot ng b mt n qu trnh ng trng hp p(AM-co-VSA) c trnh by trong bng 3.4 khi hm lng cht khi mo APS 1,5%, cht to li MBA 10%, t l monome AM/VSA 60/40, nhit 80oC, thi gian 240 pht.Bng 3.4: nh hng ca cht hot ng b mt n qu trnh ng trng hpPhn trm Span 80 (%)c im

Sn phmKh nng phn tch ht

0.05To htHt khng trn, kt dnh li

0.1To ht Ht khng trn, b kt dnh

0.15To htHt khng trn

0.2To htCc ht tch ri nhau, trn u

0.25NhKhng hnh thnh ht

T bng 3.5 cho thy, cht n nh huyn ph c nh hng ln n kh nng hnh thnh ht ca sn phm. Vi hm lng Span l 0.2% so vi lng dung mi th sn phm thu c l cc ht trn tch ri nhau v c ng u ca ht phm. Vi hm lng Span 80 khc th phn ng khng hnh thnh ht sn phm to thnh di dng nh v khi.

Chn hm lng cht hot ng b mt Span 80 l 0.2% cho qu trnh nghin cu tip theo.

3.6. C TNH HA L CA SN PHM 3.6.1. Ph hng ngoi

Ph hng ngoi ca VSA, AM, p(A,M -co-VSA) v PHA c th hin ln lt trn cc hnh 3.1, 3.2, 3.3 v 3.4 di y:

Hnh 3.1: Ph hng ngoi ca VSA

Ph hng ngoi ca vinyl sunfonic axit (VSA) (hnh 3.1) ch ra cc pic c trng ca VSA: pic 1227 cm-1 c trng cho dao ng ho tr bt i xng SO2, pic 1049cm-1 c trng cho dao ng ha tr i xng ca lin kt i S=O. Pic 1650 cm-1 c trng cho lin kt C=C.

Hnh 3.2: Ph hng ngoi ca acrylamitPh hng ngoi ca acrylamit (AM) (hnh 3.2) ch ra cc pic c trng ca AM: di ph hp c cng mnh v tr 3376 cm-1 c trng cho lin kt NH2, pic 1675 cm-1 c trng ca lin kt C=O trong amit, pic 1613cm-1 c trng cho dao ng ha tr ca lin kt i C=C.

Hnh 3.3: Ph hng ngoi ca copolyme p(AM-co-VSA)Ph hng ngoi ca copolyme p(AM-co-VSA) ch ra cc pic c trng ca AM- VSA: di ph hp c cng mnh v tr 3433 cm-1 c trng cho nhm amin - NH, pic 1654 cm-1 c trng cho dao ng bin i N-H trong mt phng, pic 1612cm-1 c trng cho dao ng ha tr ca lin kt i C=C.

Hnh 3.4: Ph hng ngoi ca PHA- VSA

Ph hng ngoi ca copolyme AM- VSA (hnh 3.4) ch ra cc pic c trng ca AM- VSA: di ph hp c cng mnh v tr 3433 cm-1 c trng cho lin kt -NH, Pic 2930 c trng cho nhm CH2 mch thng, pic 1754 cm-1 c trng ca lin kt C=O trong amit.

3.6.2. Hnh thi hc ca sn phm

Hnh thi hc ca sn phm c quan st bng nh SEM v c trnh by trn hnh 3.6. T nh c th xc nh kch thc trung bnh ca ht mt cch tng i v quan st b mt ht nghin cu kh nng phn tch ht ca sn phm.

Hnh 3.6: Mt s hnh nh SEM ca p(AM-co-VSA)(Cha sa nm 2014 thnh 2015 trong hnh)

Trn cc hnh 3.6 th hin hnh nh b mt ca cc ht sn phm iu kin nghin cu , t kt qu quan st nhn thy mu sn phm tng i ng u, ht phn tch r rng. 3.7. KHO ST NNG U NH HNG N HP PH CA NHAKt qu nghin cu nh hng ca nng n qu trnh hp ph Nd3+, Ce4+ pH=6, thi gian 180 pht c th hin trn hnh 3.7.

Hnh 3.7: nh hng ca nng n qu trnh hp ph Nd3+, Ce4+

Qua hnh 3.7 cho thy, hp ph tng nhanh trong khong nng u n 400mg/l, sau tng chm dn v ti 500mg/l th hp ph t cc i. V vy, em la chn nng ti u cho qu trnh hp ph Nd3+, Ce4+ l 500mg/l.3.8. NH HNG CA pH N KH NNG HP PH CA NHATin hnh hp ph 50ml dung dch Nd3+ bng 0,3g PHA cc pH khc nhau trong thi gian 180 pht . Sau khi hp ph hon ton em dung dch i lc v o quang xc nh nng cn li sau hp ph t tnh ra hp ph.Tin hnh phn ng nh sau: hp ph 50ml dung dch Ce4+ 500mg/l ti cc pH khc nhau: 3,4,5,6,7, trong dung mi axetat, s dng 0,15g nha PHA-VSA khuy trong thi gian 4gi nhit phng. Khi kt thc phn ng lc nha ly dung dch cn li em o quang xc nh nng cn bng v tnh hp ph.

Kt qu nghin cu nh hng ca pH n qu trnh hp ph c th hin trn hnh 3.8.

Hnh 3.8: nh hng ca pH n kh nng hp ph ca nha

T hnh 3.8 th pH = 6 ca c 2 dung dch Nd3+ v Ce4+ cho hp ph cao nht. Ly pH = 6 tip tc tin kho st cc yu t cn li nh hng n kh nng hp ph ca nha.3.9. NH HNG CA THI GIAN N KH NNG HP PH CA NHA kho st nh hng ca thi gian ti hp ph, ta s dng 0,3 g nha hp ph 50ml cha ion KLH nng 500mg/l iu chnh pH v pH ti u bng m axetat khuy trong thi gian nht nh . Kt qu thu c c trnh by trong hnh 3.9.

Hnh 3.9: nh hng ca thi gian n kh nng hp ph ca nha

T hnh 3.9 ta nhn thy thi gian hp ph Nd3+, Ce4+ ti u ca nha PHA l 180 pht.KT LUN

Qua mt thi gian nghin cu v thc hin kha lun, em tm hiu c mt s vn sau:- thu c PHA t VSA v AM bng phng php huyn ph th iu kin ti u l:

+ Nhit qu trnh tng hp l 750C

+ Thi gian phn ng 240 pht, tc khuy 300 vng/pht

+ Nng cht khi mo APS 1.5% (theo khi lng monome)

+ Nng cht to li MBA l 10% (theo khi lng monome)

+ T l monome l 60/40 (acrylamit: vinylsunfonic axit)

+ Hm lng cht hot ng b mt 0.2%

- nha PHA-VSA hp ph Nd3+ tt nht th iu kin ti u l:

+ Nng u ca Nd3+ = 1000 mg/l+ pH = 6

+ Thi gian hp ph 180 pht- nha PHA-VSA hp ph Ce4+ tt nht th iu kin ti u l:+ Nng u ca Ce3+ = 500 mg/l

+ pH = 6

+ Thi gian hp ph 180 pht

T kt qu nghin cu cho thy poly(acrylamit) v poly(hydroxamic axit) c kh nng hp th ion kim loi t him. iu ny lm c s cho vic ng dng tch cc nguyn t kim loi t him ra khi qung t him.

TI LIU THAM KHO1. Hong Nhun (2005), Nghin cu iu kin tch ring r Xeri, Lantan, Praseodim, Neodim t tinh qung t him ng Pao, Lun n Tin S Ha hc, Trng i hc Khoa hc T nhin, i hc Quc gia H Ni. 2. L Hng (2005), Gio trnh ha hc phc cht cc nguyn t t him, Khoa Ha hc, Trng i hc Khoa hc T nhin, i hc Quc gia H Ni.3. Lu Minh i, ng V Minh (2003), Phn chia v ng dng t him, Tuyn tp 10 nm thnh lp Vin Khoa hc Vt liu, H Ni.4. Ng Duy Cng Ha hc cc hp cht cao phn t.

5. Nguyn nh Hu (2000), Ha l, Tp II, Nh xut bn Gio dc.6. Nguyn Tun Anh, Ha hc cao phn t, i Hc Cng Nghip H Ni.7. Phan Th Minh Ngc, Bi Chng C s ha hc polyme (Tp 1), Nh xut bn Bch khoa H Ni, 2011.8. Trn Vn Tr (1998), Ti nguyn khong sn Vit Nam, tp IV, Vin Nghin cu a cht v Khong sn, B Cng nghip.9. Trn Vnh Diu, Trn Quang Hn (1976), Cc phn ng iu ch polyme tng hp, Nh xut bn Khoa hc k thut.10. Trng i Hc Bch Khoa H Ni (1982), Ho hc Polyme.11. Alfrey, T.;Bohrer, J. J.;Mark, H. (1952), Copolymerization: High polymer. Vol.8, Interscience.12. A.S. Sarac (1999), Redox polymerization, Prog. Polym. Sci. 24, p. 11491204.

13. Buback M. , Hippler H. (1986), Macromol Chem Rapid Commun, pp. 7-261, John Wiley and Sons, Inc., New York.

14. Buback M., Kowollik. Chr, M. Busch. CH. (2000),Chain-length dependence of free-radical termination rate deduced from laser single-pulse experiments, Wahl A. Macromol Chem Phys, Vol. 9, pp.442.

15. Chang Heon Lee,A chelating resin containing 4-(2-thiazolylazo) resorcinol as the functional group.Chromatographic application to the preconcentration and separation of some trace metal ions including uranium, Analytica Chimica ActaVolume 351, Issues 1-3, 30 September 1997, Pages 57-63.

16. Dietrich. B,HaraldCherdron, andWerner Kern (1971), Techniques of Polymer Synthesis and Characterization, Wiley - Interscience, New York.

17. Jie Cao & Yebang Tan, Synthesis of copolymer of acrylamide with sodium.

18. Kolhoff I. M., I. K. Miller (1951), J. Am. Chem. Soc. Vol. 73, p.3055-3059.

19. Liu Z., Brooks B. W. (1999), Kinetics of redox polymerization of acrylic acid in inverse dispersion and in aqueous solution, J. Polym. Sci. Part A: Polymer Chemistry, 37(3), p.313-324.

20. Mohammad Barari, Mahdi Abdollahi, and Mahmood Hemmati (2011), Synthesis and Characterization of High Molecular Weight Polyacrylamide Nanoparticles by Inverse-emulsion Polymerization, Iranian Polymer Journal, 20 (1), p.65-76.

21. Neira-Carrillo, P. Mercad-Jaque, M. Diaz-Dosque, C. Tapia-Villanueva and M. Yazdani-Pedram (2011), Influence of Chitosan Grafted Poly(vinyl Sulfonic Acid) as Template on the Calcium Carbonate Crystallization. J. Iran. Chem. Soc., Vol. 8, No. 3, September 2011, pp. 811-824.

22. Odian G. (1991), Priciples of polymerization, 3rd Ed. Wiley, New York, p. 239, p.277.

23. Peter K. Robinson. Immobilized Algal Technology for Wastewater Treatment Purposes. From "Wastewater Treatment With Algae" By Yuk-Shan Wong & Nora F.Y. Tam (Eds.). Springer. Georgetown 1998.

24. S. Durmaza, O. Okay, Acrylamide/2-acrylamido-2-methylpropane sulfonic acid sodium salt-based hydrogels: synthesis and characterization, Polymer 41 (2000) 36933704.

25. Suresh Kuarm, Peter. A. Crooks and B. Rajitha (2012), Polyvinylsulfonic acid: An Efficient and Recyclable Bronsted Acid Catalyst for Pechmann Condensation.26. Taek Seung Lee, Formation of Metal Complex in a Poly(hydroxamic acid) Resin Bead, Fibers and Polymers 2001, Vol.2, No.1, 13-17

27. Talib Hussain, Mahvash Ansari, Chemically Cross-Linked Poly(acrylic-co vinylsulfonic) Acid Hydrogel for the Delivery of Isosorbide Mononitrate, he ScientiicWorld Journal Volume 2013, Article ID 340737, 9 pages.

28. Teruyuki Okayasu, Kei Saito, Hiroyuki Nishide and Milton T. W. Hearn (2009). Preparation of a Novel Poly(vinylsulfonic acid)-grafted Solid Phase Acid Catalyst and its Use in Esterification Reactions.29. Teruyuki Okayasu, Toshiyasu Hibino, Hiroyuki Nishide (2011) Free Radical polymerization Kinetics of Vinylsulfonic Acid and Highly Acidic Properties of its Polymer . Macromol. Chem. Phys. 2011, 212, p1072p1079

30. Vinylsulfonate and its thermal stability in solution, J Polym Res (2011) 18:171178

31. Zbigniew Hubick, Studies on selective separation of Sc(III) from rare earth elements on selective ion-exchangers, Hydrometallurgy Volume 23, Issues 2-3, January 1990, Pages 319-331.

Hm lng phn gel ca sn phm

ng knh ht trung bnh ca sn phm

PAGE

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